SKF82526-J will be administered intravenously to 16 normal males maintained on either a 10meq or 300meq sodium diet to determine the effects of sodium balance on SKF82526-J induced natriuresis, Drug or vehicle will be infused over 3 hr on 2 consecutive days during a state of water diuresis. Renal function will be studies using p-aminohippurate (renal plasma flow) and inulin (GRF). The study will be repeated on the alternate diet. Lithium will be used to differentiate proximal vs. distal tubule site of action.